Cardinal Renato Martino, president of the Vatican's Council for Justice and Peace, made his comments in an interview in the Italian online newspaper Il Sussidiario.net.

"Defenceless populations are always the ones who pay. Look at the conditions in Gaza: more and more, it resembles a big concentration camp," Martino, whose informal title is Vatican "justice minister," was quoted as saying.

Pope Benedict has made several general appeals for an end to the violence in Gaza but has not openly criticised Israel.

The pope is due to visit Holy Land sites in Jordan, Israel and the Israeli-occupied West Bank in May.